Kanye West's Yeezy trainers are some of the hottest around right now. But Adidas, which produces them, just isn't fashionable enough.

Keep on Running

Adidas shares have climbed over the past five years

On Monday, the company said CEO Herbert Hainer will step down early, to be replaced by Kasper Rorsted, head of German consumer group Henkel, maker of Dial soap and Schwarzkopf shampoo.

Rorsted, no fashion expert, faces a battle on three fronts.

Miserable Run

Adidas shares have trailed rivals over the past three years

Source: Bloomberg data

First is the dominance of Nike, whose $30 billion of annual revenue dwarves Adidas's $19 billion. On the other flank is upstart Under Armour, whose quarterly revenue, while far smaller, is growing at 25 percent year-on-year, according to data compiled by Bloomberg. Then there are those pesky Athleisure brands, like Lululemon, which sell sportswear as everyday apparel. They're nibbling away at Adidas's female customers.

Sales Race

Under Armour's year-on-year sales growth is surpassing Adidas

Source: Bloomberg data

Figures for 12/31/2015 and 3/31/2016 are based on Bloomberg consensus estimates

To help defend its position, Adidas should borrow a trick from fast fashion retailers like Zara and Hennes and Mauritz. Instead of deciding what's going to sell and then pushing it out to sportswear distributors and its own stores, Adidas needs to learn to supply more of the best-sellers and cut back on what's not working -- and do this within weeks. Adidas already has already tried the technique with its fashionable Neo brand, but should expand this initiative.

That should allow Adidas to cut back on the discounts it has to offer on slow-sellers and help it to revive margins. Rorsted did just that at Henkel and he needs to repeat the trick. At 10.6 percent, Adidas's operating margin trails Nike's 12 percent and Under Armour's 14.2 percent, Bloomberg data show.

Trailing Margins

Adidas's operating margins lag both Nike and Under Armour

Source: Bloomberg data

At Henkel, Rorsted closed factories and slashed costs. There is scope for all this at Adidas, as well as disposals. The company is already seeking a buyer for TaylorMade, its golf business.

Rorsted may also consider a sale of Reebok, which generated about 1.8 billion euros ($2 billion) of annual revenue, 13 percent of the total. It looks an obvious disposal candidate, but a sale would bring the risk that Reebok would fall into the hands of an owner which could transform it into yet another challenger. Keeping Reebok would allow Adidas to develop the brand's women's athleisure business.